Enhanced Oil Recovery (EOR) is a generic term for techniques used to increase hydrocarbon production, including crude oil, natural gas, bitumen, or other hydrocarbon material, from a subterranean reservoir. Using EOR, hydrocarbon production can be dramatically increased over primary and secondary production techniques. The optimal application of EOR type depends on reservoir temperature, pressure, depth, net pay, permeability, residual oil and water saturations, porosity and fluid properties such as oil API gravity and viscosity. As EOR technology develops, there are more techniques available and they are being used on a wider range of reservoir types. Identifying the appropriate EOR for one or more reservoirs becomes difficult and EOR processes can be very expensive.
TABLE 1Identifying an appropriate EOR processMethods/ToolsLimitations/AssumptionsTaber'sGives only a broad range of properties over which classificationthe EOR method can be applied but does not give any insight into the relative success of different EOR methods if more than one is applicable for a given reservoir. Property ranges not representative of current technology.Wood's, Rai'sMore input needed to screen reservoirs than what is Modelsgenerally available, developed for 1D-2D modelsArco MiscibleLimited to miscible flooding, Requires expected Flooding Toolvolumetric sweep efficiencies, in-place and injection fluid compositionsKinder MorganLimited to CO2 flooding, black oil based, need Tooldimensionless curves to estimate recovery factorsDOE MasterBlack oil type property, Todd-Longstaff type displacementPRIZEHigh level of input for screening purposes
Existing EOR screening tools either do not capture the important factors or are limited in their application for screening reservoirs. Screening applications must be tailored to specific reservoir characteristics including permeability ranges, viscosity ranges, depth ranges as well as a plethora of other reservoir properties that may or may not be amenable to specific EOR methods.